1. Field of the Invention
This invention relates to a plasma etching apparatus employed in the manufacturing process of semiconductor elements and a transporting device used in the same.
2. Description of the Related Art
Semiconductor element manufacturing devices frequently employ transporting devices of frog leg type for transporting semiconductor wafers. The transporting devices of frog leg type are disclosed in Japanese Laid-open Patent Application Publication 60-183736 (PCT/US84/00185) and Japanese Laid-open Patent Application Publication 61-87351.
Recently, as electronic elements have been highly integrated and densified, it has become required that the amount of dust be reduced more and more in the atmosphere of the treatment chamber. In a plasma etching apparatus, for example, the transporting device is provided in a load-lock chamber whose interior can be vacuumed. Wafers are received by a sender unit under the normal atmospheric pressure, transported into the load-lock chamber, disconnected from the outer atmosphere in the load-lock chamber, and then moved into a process chamber.
However, this arrangement is still encountered with the problem that dust is brought into the process chamber, reducing the yield. The inventors of this invention found that this problem occurs from the fact that dust is particularly likely to be attached to a loading surface on which article to be treated are loaded.